MacKeeper is like 911 for your Mac. It's an easy way to manage routine tasks and keep your Mac secured, clean, reliable, fast and attended! Simple and powerful, this app will make work easier for beginners and give more flexibility to experts.

Why MacKeeper? You will never have to complain about lack of disk space, slow system performance, accidental file loss, privacy breaches, or be confused with any Mac-related questions.

Why are there so many reviews of this and no comments? A little sleuthing suggests this, from the bottom of their purchase page, may be why:
"You can get a free MacKeeper license or a discount if... you run a blog or a social account (Facebook, Twitter, YouTube, Digg etc.) with a large audience."